Abstract: An object is to provide a method and an apparatus for improving a residual stress in a tubular body, which are enabled to improve the residual stress reliably by clearly defining controlling rage for treatment conditions without depending on an installation state and configuration of the tubular body. When an outer-circumferential surface of a welded portion of a cylindrical tubular body (2) is irradiated with a laser beam that circles around an outer circumference of the tubular body (2), a heating width W in a circumferential direction heated by the laser-beam irradiation and a laser-beam moving speed V in the circumferential direction are set so that a stress in the circumferential direction in an inner surface of the tubular body (2) produced by the heating with the laser beam is at least larger than a yielding stress of a material that the tubular body (2) is made of.

Abstract: Aims are to provide a tubular-body residual-stress improving apparatus and an adjustment method thereof capable of adjusting irradiation position with favorable reproducibility, even when an optical fiber is eccentric. In the tubular-body residual-stress improving apparatus, an optical control unit (5) includes a rotational hold mechanism (9) for holding an optical fiber (6) in a manner that the optical fiber (6) is rotatable in a circumferential direction of the optical fiber (6), and, if a position of an intensity peak of the laser beam from the optical fiber (6) in an axial direction of the tubular body (2) is offset from the center of an irradiation profile, a position at which the optical fiber (6) is held in the circumferential direction is adjusted by the rotational hold mechanism (9) so as to eliminate the offset or to minimize an influence of the offset.

Abstract: A weld zone of T-piping and its neighborhood are efficiently laser-heated to remove residual stress. For this purpose, the weld zone of a T-piping (50) is irradiated and heated with a laser beam emitted from a laser head (10) to remove residual stress. At this time, a rotating travel cart (3) travels along a ring rail (2) to adjust the position of the laser head (10) in a ?-direction, a vertical slide (4) slides to adjust the position of the laser head (10) in a Z-direction, a radial slide (5) slides to adjust the position of the laser head (10) in an L-direction, an arcuate piece slide (7) slides along an arcuate piece to adjust the ?-direction of the laser head (10), a laser head support portion (9) turns to adjust the ?-direction of the laser head (10), and oscillation adjusts the position of the laser head (10) in a ?-direction.

Abstract: Aims are to provide a tubular-body residual-stress improving apparatus and an adjustment method thereof capable of adjusting irradiation position with favorable reproducibility, even when an optical fiber is eccentric. In the tubular-body residual-stress improving apparatus, an optical control unit (5) includes a rotational hold mechanism (9) for holding an optical fiber (6) in a manner that the optical fiber (6) is rotatable in a circumferential direction of the optical fiber (6), and, if a position of an intensity peak of the laser beam from the optical fiber (6) in an axial direction of the tubular body (2) is offset from the center of an irradiation profile, a position at which the optical fiber (6) is held in the circumferential direction is adjusted by the rotational hold mechanism (9) so as to eliminate the offset or to minimize an influence of the offset.

Abstract: An object is to provide a method and an apparatus for improving a residual stress in a tubular body, which are enabled to improve the residual stress reliably by clearly defining controlling rage for treatment conditions without depending on an installation state and configuration of the tubular body. When an outer-circumferential surface of a welded portion of a cylindrical tubular body (2) is irradiated with a laser beam that circles around an outer circumference of the tubular body (2), a heating width W in a circumferential direction heated by the laser-beam irradiation and a laser-beam moving speed V in the circumferential direction are set so that a stress in the circumferential direction in an inner surface of the tubular body (2) produced by the heating with the laser beam is at least larger than a yielding stress of a material that the tubular body (2) is made of.

Abstract: An aim is to provide a tubular-body residual-stress improving apparatus capable of reducing irradiation on unnecessary areas by controlling the optical paths of laser beams. In the tubular-body residual-stress improving apparatus, an optical control unit (5C) includes one pair of mirrors (21, 22) being disposed at a final stage of an optical system for a plurality of laser beams (P1-Pn) to be sharable and disposed in such a way that the mirrors are placed respectively at both sides, in the circumferential direction of the tubular body (2), of a final optical path of the laser beams to the tubular body (2), and another pair of mirrors (23, 24) being disposed at final stage of the optical system for the laser beams at both ends and disposed in such a way that the mirrors are placed respectively at both sides, in an axial direction of the tubular body (2), of final optical paths of the laser beams at both ends to the tubular body (2).

Abstract: A residual stress improving apparatus for piping, which can heat an outer peripheral surface of piping to reduce (including eliminate) the residual stress of the piping is provided. The apparatus has a laser head portion, and circumferential direction moving mechanism composed of a ring rail and a rotational travel bogie. Further, the apparatus may adjust the reflection direction of laser light so that the laser light reflected by the outer peripheral surface of the piping does not return to the laser head, and adjust the delivery direction of the laser light so that the outer peripheral surface of the bending pipe portion located forwardly, in the pipe axis direction, of the laser head is irradiated with the laser light.

Abstract: A residual stress improving apparatus for piping, which can heat an outer peripheral surface of piping to reduce (including eliminate) the residual stress of the piping, whose apparatus configuration is relatively compact, and which can also heat the outer peripheral surface of a bending pipe portion, is provided. For this purpose, the apparatus has a laser head portion 6, and circumferential direction moving means composed of a ring rail 3 and a rotational travel bogie 5.

Abstract: A weld zone of T-piping and its neighborhood are efficiently laser-heated to remove residual stress. For this purpose, the weld zone of a T-piping (50) is irradiated and heated with a laser beam emitted from a laser head (10) to remove residual stress. At this time, a rotating travel cart (3) travels along a ring rail (2) to adjust the position of the laser head (10) in a ?-direction, a vertical slide (4) slides to adjust the position of the laser head (10) in a Z-direction, a radial slide (5) slides to adjust the position of the laser head (10) in an L-direction, an arcuate piece slide (7) slides along an arcuate piece to adjust the ?-direction of the laser head (10), a laser head support portion (9) turns to adjust the ?-direction of the laser head (10), and oscillation adjusts the position of the laser head (10) in a ?-direction.

Abstract: A nonlinear optical crystal device, a wavelength conversion element, is surrounded with a heat sink having cooling fins. Cartridge heaters for uniformly heating the nonlinear optical crystal device are arranged in the heat sink, and the temperature of the cartridge heater is regulated by a heater controller. Laser light is input into the nonlinear optical crystal device, and delivered therefrom after its wavelength is converted into a shortened wavelength. When the repetition frequency of laser light is high, heating by the heaters is stopped, and cooling is effected with the heat sink. When the repetition frequency of laser light is low, heating by the heaters is carried out to maintain the temperature of the nonlinear optical crystal device to be a temperature at which a conversion efficiency is satisfactory.

Abstract: Laser light emitted from an LD apparatus is concentrated and applied onto a laser light path region A of a slab-shaped YAG crystal 21 and the neighborhood thereof with the use of a concave lens and a pair of reflecting mirrors, a duct lens, or a plurality of cylindrical lenses, whereby a concentrated applied light intensity distribution in the side surface width direction (y-axis direction) of the slab-shaped YAG crystal is formed as a double-peak distribution having maximum values P1 and P2 at opposite end portions A1 and A2 of the laser light path region of the slab-shaped YAG crystal or in the neighborhoods thereof.

Abstract: Control is exercised such that an arc discharge from a GMA electrode is performed after or simultaneously with start of oscillation of laser light from a laser oscillator, and oscillation of the laser light from the laser oscillator is stopped after or simultaneously with termination of the arc discharge from the GMA electrode. A coaxial laser beam machining head is configured such that the GMA electrode is disposed in a space portion between a first divisional laser beam and a second divisional laser beam, which have been formed by division by first and second reflecting mirrors, coaxially with the laser beams. Alternatively, the coaxial laser beam machining head is configured such that the GMA electrode is disposed in a space portion, which has been formed in a body of laser light by withdrawing part of the laser light outwardly with the use of first and second reflecting mirrors, coaxially with the body of the laser light.

Abstract: A coaxial laser beam machining head, and a laser beam machining apparatus having it are provided. The head is small in size, free from the risk of damaging optical instruments, and inexpensive.

Abstract: A cooling block 17 has three water channels 21 formed so as to be located near an LD device 18 fixed to a side surface 17c, each water channel 21 having a water channel sectional shape like an elongated hole, and being inclined relative to the side surface 17c. Heat generated by the LD device 18 is eliminated by cooling water flowing through the water channels 21. The water channel sectional area of an inlet manifold water channel is rendered not less than twice the water channel sectional area of the cooling block water channel. Irregularities are formed on the inner surface of each of the cooling block water channels. Further, an inlet portion of the cooling block water channel is chamfered or given a curvature.

Abstract: Laser light emitted from an LD apparatus is concentrated and applied onto a laser light path region A of a slab-shaped YAG crystal 21 and the neighborhood thereof with the use of a concave lens and a pair of reflecting mirrors, a duct lens, or a plurality of cylindrical lenses, whereby a concentrated applied light intensity distribution in the side surface width direction (y-axis direction) of the slab-shaped YAG crystal is formed as a double-peak distribution having maximum values P1 and P2 at opposite end portions A1 and A2 of the laser light path region of the slab-shaped YAG crystal or in the neighborhoods thereof.

Abstract: A nonlinear optical crystal device (21), a wavelength conversion element, is surrounded with a heat sink (22) having cooling fins (23a, 23b, 23c). Cartridge heaters (24) for uniformly heating the nonlinear optical crystal device (21) are arranged in the heat sink (22), and the temperature of the cartridge heater (24) is regulated by a heater controller (30). Laser light is entered into the nonlinear optical crystal device (21), and delivered therefrom after its wavelength is converted into a shortened wavelength. When the repetition frequency of laser light is high, heating by the heaters (24) is stopped, and cooling is effected with the heat sink (22). When the repetition frequency of laser light is low, heating by the heaters (24) is carried out to maintain the temperature of the nonlinear optical crystal device (21) to be a temperature at which a conversion efficiency is satisfactory.

Abstract: Control is exercised such that an arc discharge from a GMA electrode is performed after or simultaneously with start of oscillation of laser light from a laser oscillator, and oscillation of the laser light from the laser oscillator is stopped after or simultaneously with termination of the arc discharge from the GMA electrode. A coaxial laser beam machining head is configured such that the GMA electrode is disposed in a space portion between a first divisional laser beam and a second divisional laser beam, which have been formed by division by first and second reflecting mirrors, coaxially with the laser beams. Alternatively, the coaxial laser beam machining head is configured such that the GMA electrode is disposed in a space portion, which has been formed in a body of laser light by withdrawing part of the laser light outwardly with the use of first and second reflecting mirrors, coaxially with the body of the laser light.

Abstract: A laser beam machining head includes a dividing optical system for dividing laser light into two separate laser beams, and providing spacing therebetween; a condensing optical system for condensing the separate laser beams into condensed laser light, and projecting it onto a cutting site of an object to be cut; and an inner assist gas nozzle placed between the separate laser beams, a width of an opening of a tip portion of the inner assist gas nozzle being nearly equal to a cutting width. Or the tip opening of the inner assist gas nozzle is slender; or its tip side is inclined, and the angle of inclination is variable; or the relative positions of the inner assist gas nozzle and a workpiece, or the relative positions of the focal position of the condensing optical system and the workpiece are variable independently; or an outer assist gas nozzle surrounding the separate laser beams is provided.

Abstract: A coaxial laser beam machining head, and a laser beam machining apparatus having it are provided. The head is small in size, free from the risk of damaging optical instruments, and inexpensive.

Abstract: In a laser beam machine head, when a filler wire and an optical axis of a laser beam are arranged coaxially, a convex roof mirror and a concave roof mirror are combined to divide the laser beam into two separate laser beams to that no laser beam is projected onto a filler wire feed pipe. Furthermore, the filler wire is fed from outside the laser beams to a condensing position via a filler wire guide in the spacing between the separate laser beams, or an electrode supported by a water flow pipe or an electrode holding pipe is brought close to the condensing position.